Procedures for preparing photographic images in silver by diffusion transfer principles are well know in the art. For the formation of the positive silver images, a latent image contained in an exposed photosensitive silver halide emulsion is developed and almost concurrently therewith, a soluble silver complex is obtained by reaction of a silver halide solvent with the unexposed and undeveloped silver halide of said emulsion. Preferably, the photosensitive silver halide emulsion is developed with a processing composition in a viscous condition which is spread between the photosensitive element comprising the silver halide emulsion and a print-receiving element comprising, preferably, a suitable silver precipitating layer. The processing composition effects development of the latent image in the emulsion and, substantially contemporaneously therewith, forms a soluble silver complex, for example, a thiosulfate or thiocyanate, with undeveloped silver halide. This soluble silver complex is, at least in part, transported in the direction of the print-receiving element and the silver thereof is largely precipitated in the silver precipitating element to form a positive image thereon. Procedures of this description are disclosed, for example, in U.S. Pat. No. 2,543,181 issued to Edwin H. Land. See, also, Edwin H. Land, One Step Photography, Photographic Journal, Section A, pp. 7-15, January 1950.
Additive color reproduction may be produced by exposing a photosensitive silver halide emulsion through an additive color screen having film media or screen elements each of an individual additive color, such as red or green or blue, and by viewing the reversed or positive silver image formed by transfer to a transparent print-receiving element through the same or a similar screen which is suitably registered with the reversed positive image carried by the print-receiving layer.
As examples of suitable film structures for employment in additive color photography, mention may be made of U.S. Pat. Nos. 2,861,885; 2,726,154; 2,944,894; 3,536,488; 3,615,427; 3,615,428; 3,615,429; and 3,615,426.
The above-mentioned film units are disclosed to be particularly desirable for employment as a cine film for motion picture projection by reason of the inherent ability to simply and effectively process such a film employing relatively simple and stable processing compositions immediately subsequent to exposure without the necessity of providing a process and apparatus adapted to effect stripping of a separate emulsion stratum in the remainder of the film unit to provide information recordation possessing the image integrity in reproduction characteristics required for effective employment of the film
Such a film assemblage is suitably employed in a motion picture system such as that described in U.S. Pat. No. 3,615,127 issued Oct. 26, 1971, which comprises a compact motion picture cassette capable of performing the functions of exposing a photosensitive film contained therein and subsequently processing the film to develop images recorded thereon and also projecting the images or otherwise presenting them for viewing purposes. Thus, the film assemblage may be exposed, chemically processed, dried if necessary, and projected without transferring the film from its original container to any other container or even removing the film from the original cassette. The motion picture system of U.S. Pat. No. 3,615,127 includes a film processing station whereupon the exposed film strip is passed from the take-up reel, past an applicator where a moist film developing composition to develop to a visible condition images recorded on said film is applied and thence to a second reel.
The processing compositions may be applied to the films by a variety of methods such as, for example, doctor blades, extrusion heads, capillary applicators, wicks, and the like. The amount of processing composition applied to the film assemblage must be controlled within relatively narrow limits, however. Sufficient processing composition must be applied to adequately and completely permeate the film assemblage to the depth necessary and in the quantity necessary to provide the desired negative and positive images.
The processing composition employed will include an alkaline material, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, or the like, and most preferably, in a concentration providing a pH to the processing composition in excess of about 12. The processing composition may, if desired, contain the sole silver halide developing agent or agents employed or a silver halide developing agent in addition to that disposed as in the film unit. The relative proportions of the agents comprising the developing composition may be altered to suit the requirements of the operator. Thus, the developing composition may be modified by the employment of preservatives, alkalis, silver halide solvents, etc., other than those specifically mentioned. When desirable it is also contemplated to include in the developing composition components such as restrainers, accelerators, and the like. The concentration of such agents may be varied over relatively wide range commensurate with the art.
A novel film unit has now been found which is not susceptible to the deficiencies of the prior art.